SSC CGL Reasoning · Mirror and Water Images

Figures in a Mirror

A drawn figure seen in a mirror beside it: everything swaps left and right, slanting lines and arrows change direction, and nothing moves up or down.

All Mirror and Water Images notes

Why this matters

Fifty-seven questions in the bank, 54 of them from the 2023 shifts, with 22 EASY, 34 MODERATE and 1 HARD. The wrong options usually flip one part the wrong way or turn the figure upside down, so checking two or three parts in a fixed order is enough.

Concept 1 of 2: One figure flipped left to right

In a mirror beside a figure, every point keeps its height and swaps sides: what was on the left is now on the right. A line slanting up to the right now slants up to the left, and an arrow pointing right now points left.

Definition

Swaps: left and right. A part near the left edge ends up near the right edge, at the same height.
Changes direction: arrows pointing left or right, and lines slanting one way or the other.
Stays: anything pointing straight up or straight down, and the height of every part.
Clocks: a clock's mirror image shows 11:60 minus the time, so 3:00 appears as 9:00 and 2:30 as 9:30.
Fast route: strike every option that has turned the figure upside down (that is a water image). Then check one arrow or slanting line in each option left.

Worked example

In a figure, an arrow in the top-left corner points up and to the right, and a black dot sits in the bottom-right corner. A mirror stands on the right. Where are the arrow and the dot in the image, and which way does the arrow point?

Practice this conceptself-check · 4 quick reps

The same idea in a real exam question:

SSC CGL · 2024 · Tier I, 11 Sep 2024, Shift 2 · Q10Easy

Example 1 · Mirror and Water Images · Figures in a Mirror

Select the correct mirror image of the given figure when the mirror is placed at MN as shown below.

Turning the figure upside down

A mirror beside a figure never moves a part up or down. Options with the top part now at the bottom are water images and can be struck at once.

Leaving a slanting line as it was

A line from bottom-left to top-right becomes a line from bottom-right to top-left. Options that move the parts across but keep every slant the same are the setter's favourite trap.

Rotating the figure instead of flipping it

Turning a figure half a circle swaps left with right and top with bottom. A mirror swaps only left with right, so a rotated option is wrong even when its left and right look correct.

Drill 21 more on one figure flipped left to right

Concept 2 of 2: Several parts in a frame

Many mirror figures are a frame with parts in two columns or four corners. A mirror beside the frame does two things: each part moves to the other column at the same height, and each part flips left to right on the way.

Definition

1. Move: the left column becomes the right column and the right column the left. Top stays top, bottom stays bottom. 2. Flip: each part also flips: an arrow pointing right now points left, a shape with a dot on its right now has the dot on its left.

Both changes happen together. An option that moves the parts without flipping them, or flips them without moving them, is wrong.
Fast route: follow the part that is easiest to see (a black shape or a letter) to its new corner, strike the options that put it elsewhere, then check one part's flip.

Worked example

A frame holds four parts: top-left a black triangle pointing right, top-right a white circle, bottom-left the letter F, bottom-right an arrow pointing down. A mirror stands on the right. What is in each corner of the image?

Practice this conceptself-check · 4 quick reps

The same idea in a real exam question:

SSC CGL · 2024 · Tier I, 25 Sep 2024, Shift 3 · Q7Easy

Example 2 · Mirror and Water Images · Figures in a Mirror

Select the correct mirror image of the given figure when the mirror is placed at MN as shown.

Moving the parts without flipping them

When the columns swap, each part also turns to face the other way. An option with every part in its new corner but still facing the old way is wrong.

Swapping the rows as well as the columns

Swapping both rows and columns is a half turn, not a mirror image. Only the columns change sides.

Drill 34 more on several parts in a frame

Summary — formulas & gotchas at a glance

A revision cheat-sheet for the formulas and gotchas above. Click any concept name to jump back to its full explanation.

Watch out for (5)

Turning the figure upside down
→ One figure flipped left to right
Leaving a slanting line as it was
→ One figure flipped left to right
Rotating the figure instead of flipping it
→ One figure flipped left to right
Moving the parts without flipping them
→ Several parts in a frame
Swapping the rows as well as the columns
→ Several parts in a frame

Test yourself on Mirror and Water Images

20 past SSC CGL questions from this chapter, timed at 12 minutes and marked the way the exam marks it. You see your score and every answer the moment you finish. Free to start.

Take the Mirror and Water Images chapter test Drill all 57 questions